\documentclass[crop, tikz]{standalone}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}[font=\tt\scriptsize, grow=up, level 1/.style={sibling distance=30mm}, level 2/.style={sibling distance=20mm}]
	\node[align=center](0){AC{-}{-}A\\CC{-}{-}A\\ACG-A\\A-GTA\\A-G-A}
		child{node[align=center]{AGTA\\AG-A}
			child{node{AGA}}
			child{node{AGTA}}
		}
		child{node[align=center]{AC-A\\CC-A\\ACGA}
			child{node{ACGA}}
			child{node[align=center]{ACA\\CCA}
				child{node{CCA}}
				child{node{ACA}}
			}
		};
\end{tikzpicture}
\end{document}
